1. Field of the Invention
The present invention relates to a memory element, a semiconductor device including the memory element, and a method for manufacturing a memory element.
2. Description of the Related Art
In recent years, semiconductor devices including a memory element have been significantly developed. More inexpensive and convenient semiconductor devices have been required as well as more functional semiconductor devices.
As a type of read only memory (ROM), a memory element to which data can be written by users is given. By using an RFID (radio frequency identification) tag on which a memory device is mounted, merchandise management and cargo management can be easily performed while fraud such as rewriting of data in the memory element is prevented.
As typical examples of such a memory element, a fuse-type memory element, an antifuse-type memory element, and the like are given. As for the fuse-type memory element, the element is burnt off with voltage, whereby data is written, while as for the antifuse-type memory, an insulating portion is made electrically conductive (short-circuited), whereby data is written. When the fuse-type memory element is used, a problem arises in that a high voltage is needed for burning off the element or dust is generated after burning off the element. Therefore, the antifuse-type memory element is developed more actively than the fuse-type memory element. As typical examples of the antifuse-type memory element, an element in which an insulating film such as a silicon oxide film provided between conductors is dielectrically broken down so that the conductors are electrically connected, and the like are given. In addition to the above, an element in which an organic material provided between conductors is dielectrically broken down so that the conductors are electrically connected, an element in which amorphous silicon provided between conductors is silicided so that the conductors are electrically connected, and the like have also been developed (e.g., Patent Document 1). Note that in this specification, a layer which is provided between conductors to electrically connect the conductors by an irreversible reaction, such as the above silicon oxide film, organic material, and amorphous silicon, is also referred to as a “memory layer”.